usr.bin/talk/look_up.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)look_up.c        8.1 (Berkeley) 6/6/93
  30  * $FreeBSD: src/usr.bin/talk/look_up.c,v 1.5 1999/08/28 01:06:14 peter Exp $
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/socket.h>
  35 #include <protocols/talkd.h>
  36 #include <errno.h>
  37 #include "talk_ctl.h"
  38 #include "talk.h"
  39
  40 /*
  41  * See if the local daemon has an invitation for us.
  42  */
  43 int
  44 check_local(void)
  45 {
  46         CTL_RESPONSE response;
  47         CTL_RESPONSE *rp = &response;
  48
  49         /* the rest of msg was set up in get_names */
  50 #ifdef MSG_EOR
  51         /* copy new style sockaddr to old, swap family (short in old) */
  52         msg.ctl_addr = *(struct osockaddr *)&ctl_addr;
  53         msg.ctl_addr.sa_family = htons(ctl_addr.sin_family);
  54 #else
  55         msg.ctl_addr = *(struct sockaddr *)&ctl_addr;
  56 #endif
  57         /* must be initiating a talk */
  58         if (!look_for_invite(rp))
  59                 return (0);
  60         /*
  61          * There was an invitation waiting for us,
  62          * so connect with the other (hopefully waiting) party
  63          */
  64         current_state = "Waiting to connect with caller";
  65         do {
  66                 if (rp->addr.sa_family != AF_INET)
  67                         p_error("Response uses invalid network address");
  68                 errno = 0;
  69                 if (connect(sockt,
  70                     (struct sockaddr *)&rp->addr, sizeof (rp->addr)) != -1)
  71                         return (1);
  72         } while (errno == EINTR);
  73         if (errno == ECONNREFUSED) {
  74                 /*
  75                  * The caller gave up, but his invitation somehow
  76                  * was not cleared. Clear it and initiate an
  77                  * invitation. (We know there are no newer invitations,
  78                  * the talkd works LIFO.)
  79                  */
  80                 ctl_transact(his_machine_addr, msg, DELETE, rp);
  81                 close(sockt);
  82                 open_sockt();
  83                 return (0);
  84         }
  85         p_error("Unable to connect with initiator");
  86         /*NOTREACHED*/
  87         return (0);
  88 }
  89
  90 /*
  91  * Look for an invitation on 'machine'
  92  */
  93 int
  94 look_for_invite(CTL_RESPONSE *rp)
  95 {
  96         current_state = "Checking for invitation on caller's machine";
  97         ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
  98         /* the switch is for later options, such as multiple invitations */
  99         switch (rp->answer) {
 100
 101         case SUCCESS:
 102                 msg.id_num = htonl(rp->id_num);
 103                 return (1);
 104
 105         default:
 106                 /* there wasn't an invitation waiting for us */
 107                 return (0);
 108         }
 109 }